Physics Question

[AronSearle]

The principle dear lad, the principle.

Blow a firework up in front of your face, and tell me if you can "hear" the time lag prior to the flash.

The human eye can barely see the speed of sound, and obviously can't "see" the speed of light.

So you can't possibly perceive the time lag between letting the hammer go and it going.

It's silly, like you.

 

[sooey]

I've just found this, it explains what he was on about better.

According to Brian Cox in his Evening with the Stars lecture, the Pauli exclusion principle means that no electron in the universe can have the same energy state as any other electron in the universe, and that if he does something to change the energy state of one group of electrons (rubbing a diamond to heat it up in his demo) then that must cause other electrons somewhere in the universe to change their energy states as the states of the electrons in the diamond change.

But when does this change occur? Surely if the electrons are separated by a significant gap then the change cannot be instant because information can only travel at the speed of light. Wouldn't that mean that if you changed the energy state of one electron to be the same as another electron that was some distance away, then surely the two electrons would be in the same state until the information that one other electron is in the same state reaches the other electron.

Or can information be transferred instantly from one place to another? If it can, then doesn't that mean it's not bound by the same laws as the rest of the universe?

Cox was saying that the change must be instant.

 

[sooey]

so is it the same for a magnet? holding a ball baering? sudenly disapeers - what happens to the ball?

light is an electromagnetic wave.

 

[Sombrero]

so is it the same for a magnet? holding a ball baering? sudenly disapeers - what happens to the ball?

light is an electromagnetic wave.

i ment to compair magnetizm to gravty, not light

 

[joe-90]

The principle dear lad, the principle.

Blow a firework up in front of your face, and tell me if you can "hear" the time lag prior to the flash.

The human eye can barely see the speed of sound, and obviously can't "see" the speed of light.

So you can't possibly perceive the time lag between letting the hammer go and it going.

It's silly, like you.

Skip the insults and give me the maths. (he won't).

Now let me make this easier for you to comprehend.:

Get a fishing weight/plumb-bob/nut or bolt and fasten it to a piece of string/fishing line.

Spin it around over your head like a helicopter.
Now if you cut that line anywhere along its length the the effect to the weight at the end is instantaneous and it flies off at a tangent. Same with the Earth/Sun.

 

[chapeau]

....Now if you cut that line anywhere along its length the the effect to the weight at the end is instantaneous...

No it isn't.

 

[joe-90]

Yes it is.

 

[sooey]

No,it isn't. You don't need maths. You just need to know that light has a finite speed.
Therefore it will take a millionth of a millionth of a millionth of a second, or something like that for the light to travel to your eye, so nothing you percieve as instantaneous is.
That might not seem like very long but some scientists reckon the universe expanded from zilch to the size of the solar system in something like that.

 

[peaps2]

The principle dear lad, the principle.

Blow a firework up in front of your face, and tell me if you can "hear" the time lag prior to the flash.

The human eye can barely see the speed of sound, and obviously can't "see" the speed of light.

So you can't possibly perceive the time lag between letting the hammer go and it going.

It's silly, like you.

Skip the insults and give me the maths. (he won't).

Now let me make this easier for you to comprehend.:

Get a fishing weight/plumb-bob/nut or bolt and fasten it to a piece of string/fishing line.

Spin it around over your head like a helicopter.
Now if you cut that line anywhere along its length the the effect to the weight at the end is instantaneous and it flies off at a tangent. Same with the Earth/Sun.

Why dont you show us the math..?

 

[joinerjohn]

I think if the sun went out, then gravity would still be present. It's not like the sun going out would cause the mass of the sun to change instantly.
Anyway, the sun isn't likely to just "go out" is it? Scientists theorise that in millions of years time the sun will expand into a red giant. The earth and inner planets will be toast. Mankind will have either moved off this rock , by that time or we are all doomed to extinction.
Personally, I think , with all the smoking, drinking, drug taking , eating fatty foods and lack of excersise, mankind indulges in, we're all doomed anyway.

 

[doitall]

If the Sun was to completely disappear in an instant, gone poof, nothing there, we would notice the light had gone out in the 8 1/2 minutes approx it takes for light to travel here, my question is, how soon after the Sun has disappeared would the lack of the Suns gravitational pull take effect?

It would Stop global warming in a flash, or should that be bang.

 

[UriBentMySpoon]

I think if the sun went out, then gravity would still be present. It's not like the sun going out would cause the mass of the sun to change instantly.
Anyway, the sun isn't likely to just "go out" is it? Scientists theorise that in millions of years time the sun will expand into a red giant. The earth and inner planets will be toast. Mankind will have either moved off this rock , by that time or we are all doomed to extinction.
Personally, I think , with all the smoking, drinking, drug taking , eating fatty foods and lack of excersise, mankind indulges in, we're all doomed anyway.

The question was if the sun disappeared, not went out. And no it isn't likely, just a question to test the minds.

 

[EddieM]

I think if the sun went out, then gravity would still be present. It's not like the sun going out would cause the mass of the sun to change instantly.
Anyway, the sun isn't likely to just "go out" is it? Scientists theorise that in millions of years time the sun will expand into a red giant. The earth and inner planets will be toast. Mankind will have either moved off this rock , by that time or we are all doomed to extinction.
Personally, I think , with all the smoking, drinking, drug taking , eating fatty foods and lack of excersise, mankind indulges in, we're all doomed anyway.

The question was if the sun disappeared, not went out. And no it isn't likely, just a question to test the minds.

we would get a summer like 2012 is the answer.

 

[mysteryman]

The human eye can't react quickly enough for Joe89's experiments to be valid - as he knows full well. Watching television or a film would not work otherwise. If the Sun were to disappear the Earth would fly off at a tangent, and as I understand it, the gravitational effect travels at the speed of light.

Was Brian Cox talking about all the electrons in one atom, or the entire Universe?

 

[sooey]

That was the thing, he was talking about the entire universe. As though an electron on the far side of the universe which happened to be in the same state as the one he was warming up jumped into, would have to somehow know instantly and move itself to a different state.